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Pacific Northwest DEWS June Drought & Climate Outlook Webinar: June 28, 2021

Event Date
June 28, 2021
Event Time
11:00 am - 12:00 pm

According to the June 22, 2021 U.S. Drought Monitor, 79.8% of the Pacific Northwest Drought Early Warning System (DEWS) is in drought. Washington, Oregon, and Idaho all experienced their second driest March–May period on record (since 1895), and drought conditions have continued to expand throughout the region, which could contribute to increased wildfire potential. Summer is here and record-shattering heat along with it. This webinar featured conditions, climate outlooks, as well as presentations on the long-term drought effects on fire in the Northwest and on the extremes driving the western Oregon wildfires of September 2020.


Climate Recap and Current Conditions

Speaker: Larry O'Neill | Oregon Climate Service

  • There is an unprecedented heat wave across the region, accompanied by little to no cloud cover.
  • As a region, Idaho, Oregon, and Washington recorded their second driest spring (March-April-May) on record (since 1895).
  • Drought conditions are worsening across the entire Pacific Northwest.
  • The current heat wave is unprecedented in the contemporary data record.
  • Soil moisture conditions are extremely dry.
  • The entire Pacific Northwest is drier now than it was at this point last year.



Seasonal Conditions and Climate Outlook

Speaker: Troy Lindquist | Boise Weather Forecast Office, National Weather Service

  • Hot and dry conditions are expected to dominate through the 4th of July weekend.
  • The Climate Prediction Center's July through September outlook favors above-normal temperatures and below-normal precipitation.
  • Drought conditions are favored to persist across the Pacific Northwest through the summer.
  • There is above-normal significant wildland fire potential for most of the Northwest from July through September.
  • ENSO Neutral conditions are favored through the summer, with chances of La Nina increasing into the fall and winter of 2021-2022.



Long-Term Drought Effects on Fire in the Northwest: What We Know and Don't Know

Speaker: Brian Potter | Pacific Northwest Research Station, U.S. Forest Service

  • Total seasonal area is largely sensitive to the average July-August-September Palmer Drought Severity Index (PDSI).
  • No ecoregion showed sensitivity to Growing Season (March-September) PDSI.
  • Very large fire probability is greater when FM1000 decreases.
  • Shorter lead-time indices (FM100, ERC, 2-week EDDI) are strong influences on very large fire probability.



Compound Extremes Drive the Western Oregon Wildfires of September 2020

Speaker: John Abatzoglou | University of California-Merced

  • Enabled by record-setting atmospheric aridity for the broader West:
    • Increased fuel dryness and windows for large fires where fuels remain available.
    • Increased difficulty in containment simultaneously across broad regions.
  • Timing matters (it always does):
    • Exceptionally strong easterly downslope wind from the Oregon Cascades to Northern California occurred at the apex of fuel dryness.
    • Compound extremes have a long history of driving big westside fires in the Northwest.